In sharp contrast to the Du145 model, the CD44+α2β1+ LAPC9 cells were highly tumorigenic in that as few as 1 double-positive cell was able to regenerate a tumor (Table 1) and the regenerated tumor contained only a small % of CD44+α2β1+ LAPC9 cells and could be serially passaged (not shown). This evidence concerns the gene CD44 and neoplasm.